Scroll compressor and refrigeration cycle apparatus using the same

ABSTRACT

A scroll compressor includes a fixed scroll and an orbiting scroll and causes the orbiting scroll to perform an orbiting motion to form a suction chamber and a compression chamber. The scroll compressor includes a first space in a back surface center of the orbiting scroll, lubricant in a bottom of a sealed container, a second space provided further on an outer circumference side than the first space on a back surface of the orbiting scroll, a first oil leak path for causing a part of oil in the first space to leak to the second space, an oil return passage for returning most of the oil in the first space to the bottom in the sealed container, a second oil leak path for causing a part of the oil in the second space to leak to the suction chamber, and a third oil leak path.

TECHNICAL FIELD

The present invention relates to a scroll compressor used in a refrigeration cycle and a refrigeration cycle apparatus using the scroll compressor and, more particularly, to a scroll compressor including a first space, which has pressure close to discharge pressure, formed in a back surface center of an orbiting scroll and a second space, which has pressure between the discharge pressure and suction pressure, provided further on the outer circumference side than the first space.

BACKGROUND ART

As a scroll compressor used in refrigeration cycle apparatuses for refrigeration, for air conditioning, and the like, there is a scroll compressor described in JP-A-2011-58439 (Patent Literature 1) . The scroll compressor described in Patent Literature 1 includes a fixed scroll and an orbiting scroll including end plates (base plates or mirror plates) and a spiral wrap erected on the end plates, a compression chamber formed by meshing the fixed scroll and the orbiting scroll each other, a crankshaft for causing the orbiting scroll to perform an orbiting motion, an orbiting bearing provided in a back surface boss section of the orbiting scroll to support the orbiting scroll to be movable in the axial direction and rotatable with respect to an eccentric pin section of the crankshaft, a frame on a stationary side provided to be opposed to the back surface side of the orbiting scroll, a main bearing provided in the frame to rotatably support the crankshaft, a seal member that seals a space between the orbiting scroll back surface side and the frame, and a high-pressure hydraulic chamber on the inner circumference side and a backpressure chamber on the outer circumference side divided by the seal member. Lubricant having pressure substantially equal to the discharge pressure is supplied to the high-pressure hydraulic chamber and the high-pressure hydraulic chamber is maintained substantially at the discharge pressure. The backpressure chamber is maintained at pressure lower than the discharge pressure. A small hole is provided in an orbiting scroll back surface section or the frame in a portion opposed to the seal member. The small hole is alternately opened to both of the high-pressure hydraulic chamber side and the backpressure chamber side across the seal means according to the orbiting motion of the orbiting scroll. The scroll compressor includes oil supplying means for supplying oil in the high-pressure hydraulic chamber to the backpressure chamber side and an oil supply path provided in the orbiting scroll or the frame to cause the high-pressure hydraulic chamber and the backpressure chamber to communicate and supply the oil in the high-pressure hydraulic chamber to the backpressure chamber side with differential pressure.

JP-A-2005-163655 (Patent Literature 2) describes a scroll compressor including a non-orbiting scroll (a fixed scroll) including an end plate (a base plate) and a spiral body (a wrap) erected on the end plate, an orbiting scroll including an end plate (a mirror plate) and a spiral body erected on the end plate and meshing with the non-orbiting scroll to perform an orbiting motion to thereby form a suction chamber or a compression chamber between the orbiting scroll and the non-orbiting scroll, a backpressure chamber for applying a pressing force on the non-orbiting scroll to the orbiting scroll, backpressure chamber fluid inflow means for causing fluid to flow into the backpressure chamber in order to maintain the pressure of the backpressure chamber, and backpressure chamber fluid outflow means for causing the fluid flowed into the backpressure chamber to flow out to the suction chamber or the compression chamber.

In the scroll compressor described in Patent Literature 2, in the backpressure chamber fluid outflow means, a backpressure control valve for controlling differential pressure between the front and the back of the backpressure control valve, a reduced channel section, and an intermittent channel section that intermittently communicates according to the orbiting motion of the orbiting scroll member are disposed in series in a backpressure chamber fluid outflow path that connects the backpressure chamber and the suction chamber or the compression chamber.

Further, JP-A-2012-92773 (Patent Literature 3) describes a scroll compressor including a fixed scroll including a mirror plate (a base plate) and a scroll wrap erected on the mirror plate, an orbiting scroll including a mirror plate and a scroll wrap erected on the mirror plate and meshed with the fixed scroll to perform an orbiting motion to thereby form a compression chamber between the orbiting scroll and the fixed scroll, a backpressure chamber that applies an attracting force on the fixed scroll to the orbiting scroll, and an oil supply path for leading oil on a compressor discharge side into the backpressure chamber. The scroll compressor includes a compression chamber communication path including a backpressure valve that is caused to communicate with the backpressure chamber and the compression chamber after a closing start and opens and closes with differential pressure between the front and the back of the backpressure valve, the compression chamber communication path causing oil in the backpressure chamber to flow out to the compression chamber and controlling the pressure of the backpressure chamber and a suction region communication path configured to communicate with a suction region leading to the backpressure chamber and the compression chamber and not to communicate with the compression chamber after the closing start, the suction region communication path supplying the oil in the backpressure chamber to the suction region.

CITATION LIST Patent Literature

Patent Literature 1: JP-A-2011-58439

Patent Literature 2: JP-A-2005-163655

Patent Literature 3: JP-A-2012-92773

SUMMARY OF INVENTION Technical Problem

The scroll compressor described in Patent Literature 1 includes the oil supplying means and the oil supply path for supplying the oil in the high-pressure hydraulic chamber to the backpressure chamber side to make it possible to adjust an amount of the oil flowing into the backpressure chamber from the high-pressure hydraulic chamber. However, thereafter, the oil supplied to the backpressure chamber entirely flows into the suction chamber and flows to the compression chamber through the suction chamber. Therefore, no consideration is made to the fact that an oil supply amount necessary in the compression chamber is added to an oil supply amount necessary in the suction chamber and a large amount of high-temperature oil flows into the suction chamber, and sucked gas is heated and a heating loss (a suction heating loss) increases.

In the scroll compressor described in Patent Literature 2, most of oil supplied to a bearing section flows into the backpressure chamber. Thereafter, the oil in the backpressure chamber entirely flows to the suction chamber. Therefore, an extremely large amount of the oil necessary in the bearing flows into the suction chamber. No consideration is made to the fact that, since the oil far larger in amount than the oil in Patent Literature 1 flows into the suction chamber, the sucked gas is heated and the heating loss further increases and, since a large amount of the oil is supplied to the compression chamber as well, it is likely that oil compression is caused.

Further, in the scroll compressor described in Patent Literature 3, as in the scroll compressor described in Patent Literature 2, most of the oil supplied to the bearing section flows into the backpressure chamber. Since the scroll compressor described in Patent Literature 3 includes the compression chamber communication path besides the suction region communication path, it is possible to directly supply a part of the oil in the backpressure chamber to the compression chamber not through the suction chamber. Therefore, it is possible to reduce an oil supply amount from the backpressure chamber to the suction chamber to be smaller than the oil supply amount in the scroll compressor described in Patent Literature 2. However, since most of the oil supplied to the bearing section flows into the backpressure chamber, although it is possible to reduce the oil supply amount to the suction chamber to be smaller than the oil supply amount in the scroll compressor described in Patent Literature 2, it is difficult to avoid a situation in which the oil far larger in amount than the oil supply amount necessary in the suction chamber flows into the suction chamber. That is, although the oil supply amount necessary in the bearing section is far larger, for example, approximately ten times as large as the oil supply amount necessary in the suction chamber and the compression chamber, since most of the oil supplied to the bearing section flows into the backpressure chamber, it is impossible to avoid a situation in which the oil supply amount to the suction chamber also inevitably increases. Therefore, it is impossible to avoid a situation in which the sucked gas is heated and the heating loss increase. Since the large amount of the oil is supplied to the compression chamber from the backpressure chamber and merges with the oil from the suction chamber, as in Patent Literature 2, it is likely that the oil supply amount to the compression chamber increases to cause the oil compression. No consideration is made to these problems.

An object of the present invention is to obtain a scroll compressor that can control each of an oil supply amount to a bearing section, an oil supply amount to a suction chamber, and an oil supply amount to a compression chamber and realize proper amounts of oil supply to the bearing section, the suction chamber, and the compression chamber and a refrigeration cycle apparatus using the scroll compressor.

Solution to Problem

In order to achieve the object, the present invention provides a scroll compressor including a fixed scroll in which a spiral wrap is erected on a base plate and an orbiting scroll including a spiral wrap erected on a mirror plate and meshed with the fixed scroll to perform an orbiting motion, the scroll compressor causing the orbiting scroll to perform the orbiting motion with respect to the fixed scroll to thereby form a suction chamber and a compression chamber. The scroll compressor includes: a first space formed in a back surface center of the orbiting scroll, lubricant stored in a bottom of a sealed container being led to the first space, and the first space having pressure close to discharge pressure; a second space provided further on an outer circumference side than the first space on a back surface of the orbiting scroll, the second space having pressure between the discharge pressure and suction pressure; a first oil leak path for causing a part of oil in the first space to leak to the second space; an oil return passage for returning most of the oil in the first space to the bottom in the sealed container; a second oil leak path for causing a part of the oil in the second space to leak to the suction chamber; and a third oil leak path for allowing the oil in the second space to escape to the compression chamber to adjust the pressure in the second space according to a difference between pressure in the compression chamber and the pressure in the second space.

Other characteristics of the present invention reside in a refrigeration cycle apparatus for refrigeration and air conditioning configured using the scroll compressor configured as explained above.

Advantageous Effect of Invention

According to the present invention, there is an effect that it is possible to obtain a scroll compressor that can control each of an oil supply amount to a bearing section, an oil supply amount to a suction chamber, and an oil supply amount to a compression chamber and realize proper amounts of oil supply to the bearing section, the suction chamber, and the compression chamber and a refrigeration cycle apparatus using the scroll compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view showing a first embodiment of a scroll compressor of the present invention.

FIG. 2 is a view showing a state in which a fixed scroll and an orbiting scroll shown in FIG. 1 are meshed with each other and is a view of the fixed scroll and the orbiting scroll viewed from a II-II direction in FIG. 1.

FIG. 3 is a perspective view of the orbiting scroll shown in FIG. 1 viewed from above.

FIG. 4 is an enlarged sectional view around a backpressure valve in the scroll compressor shown in FIG. 1.

FIG. 5 is a view for explaining another example of the orbiting scroll and is a perspective view equivalent to FIG. 2.

FIG. 6 is a view for explaining a second embodiment of the scroll compressor of the present invention and is a view equivalent to FIG. 4.

FIG. 7 is a view for explaining a third embodiment of the present invention and is a refrigeration cycle configuration diagram showing an example of a refrigeration cycle apparatus using the scroll compressor.

DESCRIPTION OF EMBODIMENTS

Specific embodiments of the present invention are explained below with reference to the drawings. Note that in the figures, portions denoted by the same reference numerals and signs indicate the same or equivalent portions.

First Embodiment

A first embodiment of a scroll compressor of the present invention is explained with reference to FIG. 1 to FIG. 5. FIG. 1 is a longitudinal sectional view showing the first embodiment of the scroll compressor of the present invention. FIG. 2 is a view showing a state in which a fixed scroll and an orbiting scroll shown in FIG. 1 are meshed with each other and is a view of the fixed scroll and the orbiting scroll viewed from a II-II direction in FIG. 1. FIG. 3 is a perspective view of the orbiting scroll shown in FIG. 1 viewed from above. FIG. 4 is an enlarged sectional view around a backpressure valve in the scroll compressor shown in FIG. 1. FIG. 5 is a view for explaining another example of the orbiting scroll and is a perspective view equivalent to FIG. 3.

First, the overall configuration of the scroll compressor in this embodiment is explained with reference to FIG. 1.

A scroll compressor 1 is configured by housing a compression mechanism section 2, a motor unit 16, and the like in a case (a sealed container) 9.

In the compression mechanism section 2, an orbiting scroll 8 is meshed with a fixed scroll 7 fixed to a frame 17 to form compression chambers 13. The orbiting scroll 8 is caused to perform an orbiting motion via a crankshaft (a rotating shaft) 10 according to rotation of the motor unit 16, whereby the capacity of the compression chambers 13 is reduced to perform compressing operation.

According to the compressing operation, working fluid is sucked into a suction chamber 20 (see FIG. 3) from a suction port 14 . The sucked working fluid is discharged from a discharge port 15 to a discharge space 54 in the case 9 through a compression stroke in the compression chambers 13. The working fluid discharged to the discharge space 54 flows to a motor chamber 52 passing through a passage (not shown in the figure) formed in the outer circumference of the fixed scroll 7 and the outer circumference of the frame 17. Thereafter, the working fluid is discharged to the outside of the case 9 from a discharge pipe 6.

The fixed scroll 7 includes a disk-like base plate 7 a, a wrap 7 b spirally erected on the base plate 7 a, and a supporting section 7 d located on the outer circumference side of the base plate 7 a, including a mirror plate surface 7 e having height substantially the same as the height of the distal end face of the wrap 7 b and provided in a cylinder shape to surround the wrap 7 b. The surface of the base plate 7 a, on which the wrap 7 b is erected, is called teeth bottom 7 c because the surface is present among spirals of the wrap 7 b.

The mirror plate surface 7 e is formed as a sliding surface on which the supporting section 7 d of the fixed scroll 7 is in contact with a mirror plate 8 a of the orbiting scroll 8. In the fixed scroll 7, the supporting section 7 d is fixed to the frame 17 by a bolt or the like. The frame 17 integrally combined with the fixed scroll 7 is fixed to the case 9 by fixing means such as welding.

The orbiting scroll 8 is disposed to be opposed to the fixed scroll 7. The orbiting scroll 8 is turnably provided in the frame 17 with the wrap 7 b of the fixed scroll 7 and a wrap 8 b of the orbiting scroll 8 meshed with each other. The orbiting scroll 8 includes the spiral wrap 8 b erected from a teeth bottom 8 c, which is the surface of the disk-like mirror plate 8 a, and an orbiting boss section (a boss section) 8 d provided in the back surface center of the mirror plate 8 a. The surface of the outer circumferential section of the mirror plate 8 a in contact with the fixed scroll 7 is formed as a mirror plate surface 8 e of the orbiting scroll 8.

The distal end portion (a wrap teeth tip) of the wrap 8 b of the orbiting scroll 8 is configured to be opposed to the teeth bottom 7 c of the fixed scroll 7 with a very small gap. Similarly, the distal end portion (the wrap teeth tip) of the wrap 7 b of the fixed scroll 7 is configured to be opposed to the teeth bottom 8 c of the orbiting scroll 8 with a very small gap.

An oil reservoir 53 for storing lubricant (refrigerator oil) is provided in the bottom of the case 9 of a sealed container structure in which the compression mechanism section 2, the motor unit 16, and the like are housed. The motor unit 16 is configured by a rotor 16 a and a stator 16 b. The crankshaft 10 is integrally fixed to the rotor 16 a. The crankshaft 10 is rotatably supported on the frame 17 via a main bearing 5 and is coaxial with the center axis of the fixed scroll 7.

An eccentric crank section 10 a is provided at the distal end of the crankshaft 10. The crank section 10 a is inserted into an orbiting bearing 11 provided in the orbiting boss section 8 d of the orbiting scroll 8. The orbiting scroll 8 is configured to be capable of orbiting according to rotation of the crankshaft 10.

The center axis of the orbiting scroll 8 is in an eccentric state by a predetermined distance with respect to the center axis of the fixed scroll 7. The wrap 8 b of the orbiting scroll 8 is superimposed on the wrap 7 b of the fixed scroll 7 while being shifted by a predetermined angle (in general, 180 degrees) in the circumferential direction.

Reference numeral 12 denotes an Oldham ring for causing the orbiting scroll 8 to perform an orbiting motion relatively to the fixed scroll 7 while restraining the orbiting scroll 8 not to revolve.

FIG. 2 is a view for explaining a meshing state of the fixed scroll 7 and the orbiting scroll 8 and is a view of the fixed scroll 7 and the orbiting scroll 8 viewed from a II-II direction in FIG. 1. Therefore, concerning the orbiting scroll 8, the orbiting scroll wrap 8 b is shown as a cross section.

A portion equivalent to the outer circumference of the mirror plate 8 a of the orbiting scroll 8 is indicated by an alternate long and two short dashes line (an imaginary line).

As shown in FIG. 2, a plurality of crescent compression chambers 13 (an orbiting-inner-line-side compression chamber 13 a and orbiting-outer-line-side compression chambers 13 b) are formed between the fixed scroll wrap 7 b and the orbiting scroll wrap 8 b. When the orbiting scroll 8 is caused to perform an orbiting motion, as the compression chambers 13 move in the direction to the center, capacities of the compression chambers 13 are continuously reduced.

Reference numeral 20 denotes a suction chamber and a space halfway in suction of the fluid. The suction chamber 20 changes to the compression chambers 13 at a point in time when the phase of the orbiting motion of the orbiting scroll 8 advances and confining of the fluid is completed.

As shown in FIG. 1 and FIG. 2, the suction port 14 is provided in the fixed scroll 7. The suction port 14 is drilled on the outer circumference side of the base plate 7 a of the fixed scroll 7 to communicate with the suction chamber 20.

The discharge port 15 is drilled near the spiral center of the base plate 7 a of the fixed scroll 7 to communicate with the compression chamber 13 on the innermost circumference side.

When the crankshaft 10 is rotated by the motor unit 16 shown in FIG. 1, the orbiting scroll 8 performs an orbiting motion with a predetermined orbiting radius centering on the center axis of the fixed scroll 7. Consequently, the working fluid sucked from the suction port 14, for example, refrigerant gas (hereinafter simply referred to as fluid) circulating in a refrigeration cycle is sequentially compressed in the compression chambers 13. The compressed working fluid is discharged from the discharge port 15 to the discharge space 54. As explained above, the working fluid is supplied to, for example, the refrigeration cycle outside the compressor from the discharge pipe 6.

An oil supply pump 21 of a displacement type or a centrifugal type is provided at the lower end of the crankshaft 10. According to the rotation of the crankshaft 10, the oil supply pump 21 also rotates, sucks the lubricant stored in the oil reservoir 53 in the bottom of the case 9 from a lubricant suction port 22 a of an oil supply pump case 22, and discharges the lubricant from a discharge port 21 a of the oil supply pump 21. The discharged lubricant is sent to a space in the orbiting boss section 8 d at the upper end of the crank section 10 a through a through-hole (an oil supply hole) 3 formed in the axial direction in the crankshaft 10.

Note that a part of the lubricant flowing through the through-hole 3 is sent to a sub-bearing 23 via a lateral hole 24 provided in the crankshaft 10. After lubricating the sub-bearing 23, the lubricant returns to the oil reservoir 53 in the bottom of the case 9. The most of the other lubricant flowing through the through-hole 3 reaches the orbiting boss section space at the upper end of the crank section 10 a, passes through an oil groove 57 provided on the outer circumferential surface of the crank section 10 a, and lubricates the orbiting bearing 11. Thereafter, after lubricating the main bearing 5 provided below the orbiting bearing 11, the lubricant is returned to the oil reservoir 53 in the bottom of the case 9 through an oil return passage 26 configured by an oil discharge hole 26 a and an oil discharge pipe 26 b.

The orbiting boss section space formed by the oil groove 57, the orbiting bearing 11, and the like and a space in which the main bearing 5 is housed (a space formed by the frame 17, the crankshaft 10, a frame seal 56, a brim section 34 provided in the orbiting boss section 8 d, and a seal member 32) are collectively referred to as first space 33. The first space 33 is a space having pressure close to the discharge pressure.

Most of the lubricant flowed into the first space 33 for the lubrication of the main bearing 5 and the orbiting bearing 11 returns to the oil reservoir 53 in the bottom of the case 9 passing through the oil discharge hole 26 a and the oil discharge pipe 26 b (an oil return passage). A part of the lubricant flows into a backpressure chamber 18, which is a second space having pressure between the discharge pressure and the suction pressure provided further on the outer circumference side than the first space 33, via a first oil leak path provided between the upper end face of the seal member 32 and the end face of the brim section 34 of the orbiting boss section 8 d by an amount necessary for lubrication of the Oldham ring 12, lubrication of sliding sections of the fixed scroll 7 and the orbiting scroll 8, and seal (sealing) of, for example, distal end gaps of the wraps 7 b and 8 b.

The seal member 32 is provided, together with a wavy spring (not shown in the figure), in an annular groove 31 provided on a surface opposed to the brim section 34 of the frame 17 and partitions the first space 33 having the discharge pressure and the backpressure chamber (the second space) 18 having the pressure in the middle of the suction pressure and the discharge pressure.

The first oil leak path is configured by, for example, one or a plurality of slits 60 (grooves) long in the radial direction provided in the brim section 34 of the orbiting boss section 8 d and the seal member 32. The slits 60 are disposed to intermittently straddle the seal member 32 according to the orbiting motion of the orbiting scroll 8 to be configured to cause the first space 33 and the backpressure chamber 18 to intermittently communicate.

Consequently, it is possible to cause the oil to flow into the backpressure chamber 18 from the first space 33 via the slits 60, which are very small gaps, according to a pressure difference between the first space 33 and the backpressure chamber 18.

Note that the slits 60 are not limited to be disposed to intermittently straddle the seal member 32 according to the orbiting motion of the orbiting scroll 8 and may be disposed to always straddle the seal member 32.

Instead of the slits 60, one or a plurality of, that is, one or more holes (e.g., circular grooves) functioning as oil reservoirs are provided in the brim section 34 of the orbiting boss section. The holes are configured to perform a circular motion straddling the seal member 32 according to the orbiting motion of the orbiting scroll 8. Consequently, the holes move between the first space 33 and the backpressure chamber 18. It is possible to accumulate, in the holes, the lubricant in the first space 33 and intermittently transfer the lubricant to the backpressure chamber 18 and discharge the lubricant. It is possible to supply the oil in the first space 33 to the backpressure chamber 18. The first oil leak path may be configured in this way.

In this embodiment, a part of the lubricant flowed into the backpressure chamber 18 flows into the suction chamber 20 via a second oil leak path explained below. The part of the lubricant lubricates wrap sliding surfaces, wrap distal end gaps, and the like and is used for seal of, for example, a space between compression chambers.

The remainder of the lubricant flowed into the backpressure chamber 18 flows into the compression chambers 13 via a third oil leak path explained below. The remainder of the lubricant lubricates wrap sliding surfaces, wrap distal end gaps, and the like of the compression chambers and is used for seal of the space between the compression chambers.

In this way, in this embodiment, the lubricant can be caused to leak from the first space 33 to the second space (the backpressure chamber) 18 via the first oil leak path by an amount necessary for the lubrication of the wrap sliding surfaces and the wrap distal end gaps and the seal of the space between the compression chambers. The remaining lubricant can be returned to the oil reservoir 53 via the oil discharge hole 26 a and the oil discharge pipe 26 b after the lubrication of the bearing sections. Therefore, in this embodiment, it is possible to independently control an oil supply amount necessary for the lubrication of the bearing sections and an oil supply amount to the backpressure chamber 18. Therefore, it is possible to reduce the oil supply amount to the backpressure chamber 18 to the necessary minimum.

The lubricant flowed into the backpressure chamber 18 can be supplied to the suction chamber 20 via the second oil leak path by a necessary oil supply amount. The remaining lubricant is supplied to the compression chambers 13 via the third oil leak path. Therefore, it is possible to respectively reduce the oil supply amounts to the suction chamber 20 and the compression chambers 13 to the necessary minimums. Therefore, it is possible to minimize a suction heating loss in the suction chamber 20. It is possible to prevent oil compression, a heating loss, and the like due to excessive supply of the oil in the compression chambers 13. Therefore, it is possible to realize a scroll compressor having high efficiency and high reliability.

The configuration of the second oil leak path is explained with reference to FIG. 2 and FIG. 3.

As shown in FIG. 3, reference numeral 64 denotes an oil hole (a groove) provided on the mirror plate surface 8 e of the orbiting scroll 8 and functioning as an oil reservoir. As shown in FIG. 2, according to the orbiting motion of the orbiting scroll 8, the oil hole 64 draws a track 65 shown in FIG. 2 and intermittently communicates with the backpressure chamber (the second space) 18 and a groove section 66 that communicates with and the suction chamber 20.

In a state in which the oil hole 64 communicates with the backpressure chamber 18, the oil in the backpressure chamber 18 (pressure is the pressure in the middle of the discharge pressure and the suction pressure) is accumulated in the oil hole 64. When the oil hole 64 communicates with the groove section 66 (pressure is the suction pressure) according to the orbiting motion of the orbiting scroll 8, the oil in the oil hole 64 is led into the suction chamber 20 through the groove section 66 according to a pressure difference.

By repeating this action, the oil in the backpressure chamber 18 is sequentially transferred to the suction chamber 20. By adjusting the capacity of the oil hole 64 and the number of oil holes 64, it is possible to optionally adjust the oil supply amount from the backpressure chamber 18 to the suction chamber 20.

The configuration of the third oil leak path is explained with reference to FIG. 1, FIG. 2, and FIG. 4.

First, the function of the backpressure chamber (the second space) 18 is explained. In the scroll compressor 1, a force (a separating force) in the axial direction for separating the fixed scroll 7 and the orbiting scroll 8 is generated by the compression action of the scroll compressor 1. When a so-called disengaging phenomenon of the orbiting scroll 8 occurs in which both the scrolls are separated by the force in the axial direction, sealability of the compression chambers 13 is deteriorated and to reduce compressor efficiency.

Therefore, the backpressure chamber 18 having the pressure between the discharge pressure and the suction pressure is provided on the back surface side of the mirror plate 8 a of the orbiting scroll 8. The separating force is cancelled and the orbiting scroll 8 is pressed against the fixed scroll 7 by pressure (backpressure) of the backpressure chamber 18. When a pressing force at this point is too large, a sliding loss of the mirror plate surface 8 e of the orbiting scroll 8 and the mirror plate surface 7 e of the fixed scroll 7 increases and the compressor efficiency decreases.

That is, an optimum value is present for the backpressure.

When the backpressure is too small, the sealability of the compression chambers is deteriorated and a heat fluid loss increases. When the backpressure is too large, the sliding loss increases. Therefore, it is important for improvement of performance and improvement of reliability of the compressor to maintain the backpressure at the optimum value.

In order to obtain the optimum backpressure value, in the scroll compressor in this embodiment, as shown in FIG. 1, the third oil leak path (the compression chamber communication path) including a backpressure valve 61 for adjusting the backpressure of the backpressure chamber 18 is included in the supporting section 7 d of the fixed scroll 7.

The configuration of the third oil leak path is explained in detail with reference to FIG. 4, which is an enlarged view showing the configuration around the backpressure valve 61 in FIG. 1.

The third oil leak path (a compression chamber communication path) is configured by a backpressure valve inflow path (a space communicating with the backpressure chamber 18) 62 a that causes the backpressure chamber 18 and the backpressure valve 61 to communicate, a backpressure valve outflow path (a space communicating with the compression chambers 13) 62 c that causes the backpressure valve 61 and the compression chambers 13 to communicate, and a space 62 b in which the backpressure valve 61 is housed. In the backpressure valve 61, a valve 61 a is disposed to partition the backpressure valve inflow path 62 a and the backpressure valve outflow path 62 c. The valve 61 a is provided to be pressed against an opening section of the backpressure valve inflow path 62 a by a spring 61 b fixed to a stopper 61 c.

When pressure, that is, backpressure in the backpressure valve inflow path 62 a is higher than a total of pressure in the space 62 b, that is, pressure in the compression chambers into which the fluid is led via the backpressure valve outflow path 62 c and pressure corresponding to a pressing force of the spring 61 b, the valve 61 a moves upward and causes the backpressure valve inflow path 62 a and the backpressure valve outflow path 62 c to communicate. That is, when the pressure in the backpressure chamber 18 is higher than a certain value, the backpressure valve 61 allows the fluid in the backpressure chamber 18 to escape to the compression chambers 13 and adjusts the backpressure of the backpressure chamber 18 to a proper value.

The oil flowed into the compression chambers 13 lubricates the wrap sliding surfaces, the wrap distal end gaps, and the like and is used for seal of the space between the compression chambers. Thereafter, the oil is discharged to the discharge space 54 from the discharge port 15. Apart of the discharged oil is discharged from the discharge pipe 6 to the refrigeration cycle, for example, together with the refrigerant gas. The remainder is separated from the refrigerant gas in the case 9 and stored in the oil reservoir 53 in the bottom of the case.

In the conventional scroll compressors described in Patent Literature 2 and Patent Literature 3, substantially the entire lubricant supplied to the first space, that is, the bearing section flows into the backpressure chamber 18 and thereafter flows to the suction chamber 20 and the compression chambers 13. Therefore, the oil supply amount to the suction chamber 20 and the oil supply amount to the compression chambers 13 are excessively large, the refrigerant is heated by the high-temperature lubricant and expands, the suction heating loss increases, and a refrigerant amount that can be sucked to the suction chamber 20 decreases. Therefore, volume efficiency decreases. Substantially the entire lubricant supplied to the bearing section flows into the compression chambers 13. Therefore, an increase in a heating loss and an increase in compression power by oil compression occur.

On the other hand, in the scroll compressor described in Patent Literature 1, it is possible to independently control the oil supply amount to the backpressure chamber 18. However, when a lubricant amount flowing into the backpressure chamber 18 is reduced in order to suppress the suction heating loss in the suction chamber, sufficient oil supply to the compression chambers 13 cannot be performed. A sealing effect by the oil in the compression chambers 13 decreases. Therefore, a leak loss increases.

That is, in the conventional scroll compressors, appropriate amounts of the lubricant cannot be respectively supplied to the suction chamber 20 and the compressor 13.

On the other hand, in this embodiment, the oil supply amount to the bearing sections and the oil supply amount to the backpressure chamber can be independently controlled by the first oil leak path. The oil supply amount supplied from the backpressure chamber 18 to the suction chamber 20 are independently controlled by the second oil leak path. Further, the scroll compressor includes the third oil leak path for supplying the oil from the backpressure chamber 18 to the compression chambers 13 after the completion of a suction process via the backpressure valve 61. Therefore, it is possible to appropriately adjust the oil supply amounts respectively to the bearing sections, the suction chamber 20, and the compression chambers 13.

Note that, in this embodiment, the backpressure valve outflow path 62 c communicates with the compression chambers 13 after the completion of the suction process and the start of the compression. That is, the compression chambers 13 are compression chambers halfway in compression after the completion of the suction process and are compression chambers separated from the suction chamber 20. As shown in FIG. 2, the backpressure valve outflow path 62 c is in a position that alternately communicates with both of the orbiting outer line compression chambers 13 b and the orbiting inner line compression chamber 13 a according to the orbiting motion of the orbiting scroll.

Note that 63 shown in FIG. 4 denotes a stop cock. The stop cock 63 seals and closes an end portion of a lateral hole formed to provide the backpressure valve outflow path 62 c.

In this embodiment, since the third oil leak path including the backpressure valve 61 is provided, it is possible to directly supply the oil in the backpressure chamber 18 to the compression chambers 13 via the backpressure valve 61 not through the suction chamber 20. An oil supply amount to the compression chambers 13 is a difference between an oil supply amount from the first space 33 to the backpressure chamber 18 by the first oil leak path and an oil supply amount from the backpressure chamber 18 to the suction chamber 20 by the second oil leak path. That is, the oil is supplied to the backpressure chamber 18 from the first space 33 via the first oil leak means. However, the oil is led into the suction chamber by only an amount determined by the second oil leak path. The remaining oil is led into the compression chambers 13.

Therefore, by adjusting respective oil supply amounts of the first oil leak path and the second oil leak path, it is possible to control the oil supply amount to the suction chamber and the oil supply amount to the compression chambers respectively to appropriate amounts.

In general, an oil supply amount necessary for seal of the compression chambers 13 is larger than an oil supply amount necessary for seal of the suction chamber. Therefore, for example, in the scroll compressor described in Patent Literature 1, when the oil supply amount in the first oil leak path is set to the oil supply amount necessary for seal of the compression chambers, the oil supply becomes excessive and the suction heating loss increases in the suction chamber 20. Conversely, when the oil supply amount in the first oil leak path is set to a small oil supply amount only necessary for seal of the suction chamber 20, the oil supply becomes in sufficient, the sealing effect by the oil decreases, and a leak loss increases in the compression chambers.

On the other hand, in this embodiment, it is possible to supply appropriate amounts of the oil respectively to the suction chamber and the compression chambers. Therefore, compared with the scroll compressor described in Patent Literature 1, it is possible to reduce the suction heating loss and the leak loss.

Further, the backpressure valve outflow path 62 c is formed in the position that alternately communicates with both of the orbiting outer line compression chambers 13 b and the orbiting inner line compression chamber 13 a according to the orbiting motion of the orbiting scroll. Therefore, it is possible to supply the oil to both the compression chambers. It is possible to avoid a deficiency in which oil supply is insufficient in any one of the compression chambers 13.

By setting the oil supply amounts to set the oil supply amount by the first oil leak path larger than the oil supply amount by the second oil leak path, it is possible to supply a difference between the oil supply amounts by the first oil leak path and the second oil leak path to the compression chambers 13. Therefore, it is possible to surely secure the oil supply amount to the compression chambers 13.

Further, if this embodiment is applied to a scroll compressor that uses, as working fluid, a refrigerant that easily has high temperature and has an adiabatic exponent larger than 1.09, for example, R32, it is possible to further reduce the suction heating loss. It is possible to obtain a scroll compressor having higher efficiency.

Note that, in the embodiment explained above, as shown in FIG. 3, the example is explained in which the second oil leak path is configured by providing the circular oil hole (groove) 64 on the mirror plate surface 8 e of the orbiting scroll 8. However, the present invention is not limited to this. That is, as shown in FIG. 5, instead of the oil hole 64, a shallow slit (groove) 67 may be provided. The slit 67 may always or intermittently communicate with the backpressure chamber 18 and the groove section 66, which communicates with the suction chamber 20, to lead the oil in the backpressure chamber 18 into the suction chamber 20 according to a pressure difference. Even in this case, it is possible to control an oil supply amount by adjusting the depth, the width, and the length of the slit, the number of slits, or the like.

Second Embodiment

A second embodiment of the scroll compressor of the present invention is explained with reference to FIG. 6. FIG. 6 is a view equivalent to FIG. 4 referred to above. In FIG. 6, portions denoted by reference numerals and signs same as those in FIG. 1 to FIG. 5 are the same or equivalent portions.

In the second embodiment, as in the first embodiment, an oil supply amount to the bearing sections and an oil supply amount to the backpressure chamber can be independently controlled by the first oil leak path. An oil supply amount supplied from the backpressure chamber 18 to the suction chamber 20 can be independently controlled by the second oil leak path. However, in the second embodiment, the scroll compressor does not include the third oil leak path for supplying oil from the backpressure chamber 18 to the compression chambers 13 via the backpressure valve 61 shown in FIG. 4. The third oil leak path in the second embodiment is not included in the supporting section 7 d of the fixed scroll 7. As shown in FIG. 6, the third oil leak path is configured by a backpressure hole 68 formed in the mirror plate 8 a of the orbiting scroll 8.

The backpressure hole 68 is provided in the orbiting scroll mirror plate 8 a to cause the backpressure chamber (the second space) 18 and the compression chambers 13 after the completion of the suction process and the start of compression to communicate. That is, the backpressure hole 68 is provided in a position that communicates with only the compression chambers 13 separated from the suction chamber 20. The pressure in the backpressure chamber 18 can be maintained at a value close to average pressure in the compression chambers 13 by the backpressure hole 68.

As explained above, the scroll compressor includes the first oil leak path, the second oil leak path, and the backpressure hole 68 (the third oil leak path). Therefore, as in the first embodiment, it is possible to appropriately adjust the oil supply amounts respectively to the bearing sections, the suction chamber 20, and the compression chambers 13.

According to the embodiments of the present invention explained above, it is possible to control each of the oil supply amount to the bearing sections, the oil supply amount to the suction chamber, and the oil supply amount to the compression chambers, realize proper amounts of oil supply to the bearing sections, the suction chamber, and the compression chambers, and realize a scroll compressor having a small loss and high efficiency. Note that, in general, the refrigerant is also included in the oil (the lubricant) leaking from the first to third oil leak paths. However, in the present invention, the oil including the refrigerant is also explained as the oil.

Third Embodiment

A third embodiment of the present invention is explained with reference to FIG. 7. FIG. 7 is a refrigeration cycle configuration diagram showing an example of a refrigeration cycle apparatus for refrigeration and air conditioning using the scroll compressor of the present invention explained above.

In this embodiment, an example in which the scroll compressor of the present invention is applied to an air conditioner functioning as a refrigeration cycle apparatus is explained with reference to FIG. 7. In FIG. 7, reference numeral 1 denotes a scroll compressor, 43 denotes a four-way valve, 40 denotes an outdoor side heat exchanger (functioning as a condenser during cooling operation and functioning as an evaporator during heating operation), 41 denotes an expansion valve configured by an electronic expansion valve or the like, and 42 denotes an indoor side heat exchanger (functioning as an evaporator during cooling operation and functioning as a condenser during heating operation). These devices are sequentially connected by a refrigerant pipe to configure a refrigeration cycle of the air conditioner. In this embodiment, as the scroll compressor 1, any one of the scroll compressors described in the embodiments is used.

By combining the scroll compressor described in any one of the embodiments of the present invention explained above with the air conditioner shown in FIG. 7, it is possible to greatly improve operation efficiency of the air conditioner. It is possible to greatly improve Annual Performance Factor (APF) of the air conditioner. It is possible to obtain an air conditioner (a refrigeration cycle apparatus) having small power consumption throughout the year, wide in an operation range, and convenient for use.

Note that, in the third embodiment, the scroll compressor of the present invention is applied to the air conditioner including one outdoor side heat exchanger 40 and one indoor side heat exchanger 42. However, the scroll compressor of the present invention can also be applied to, for example, a multi-type air conditioner including a plurality of the indoor side heat exchangers 42. Further, the scroll compressor of the present invention can also be applied to refrigeration cycle apparatuses such as an air conditioner exclusive for cooling and a refrigerator.

As explained above, according to the embodiments of the present invention, it is possible to control each of the oil supply amount to the bearing sections, the oil supply amount to the backpressure chamber, the oil supply amount to the suction chamber, and the oil supply amount to the compression chambers to proper oil supply amounts necessary for the bearing sections, the backpressure chamber, the suction chamber, and the compression chambers. Therefore, it is possible to obtain a scroll compressor having high efficiency and a refrigeration cycle apparatus for refrigeration and air conditioning using the scroll compressor.

Note that the present invention is not limited to the embodiments and includes various modifications.

The embodiments are explained in detail in order to clearly explain the present invention. The embodiments are not always limited to embodiments including all of the explained components. Further, addition of other components, deletion, and substitution can be performed concerning a part of the components in the embodiments.

Reference Signs List

1: scroll compressor

2: compression mechanism section

3: through-hole (oil supply hole)

5: main bearing

6: discharge pipe

7: fixed scroll

7 a: base plate

7 b: wrap

7 c: teeth bottom

7 d: supporting section

7 e: mirror plate surface

8: orbiting scroll

8 a: mirror plate

8 b: wrap

8 c: teeth bottom

8 d: orbiting boss section (boss section)

8 e: mirror plate surface

9: case (sealed container)

10: crankshaft (rotating shaft)

10 a: crank section

11: orbiting bearing

12: Oldham ring

13: compression chamber

13 a: orbiting-inner-line-side compression chamber

13 b: orbiting-outer-line-side compression chamber

14: suction port

15: discharge port

16: motor unit

16 a: rotor

16 b: stator

17: frame

18: backpressure chamber

20: suction chamber

21: oil supply pump

21 a: oil supply pump discharge port

22: oil supply pump case

22 a: lubricant suction port

23: sub-bearing

24: lateral hole

26: oil return passage (26 a: oil discharge hole, 26 b: oil discharge pipe)

31: annular groove

32: seal member

33: first space

34: brim section

40: outdoor side heat exchanger

41: expansion valve

42: indoor side heat exchanger

43: four-way valve

52: motor chamber

53: oil reservoir

54: discharge space

56: frame seal

57: oil groove

60: slit (groove)

61: backpressure valve

61 a: valve

61 b: spring

61 c: stopper

62 a: backpressure valve inflow path

62 b: space

62 c: backpressure valve outflow path

63: stop cock

64: oil hole (groove)

65: track of the oil hole

66: groove section

67: slit (groove)

68: backpressure hole 

1. A scroll compressor including a fixed scroll in which a spiral wrap is erected on a base plate and an orbiting scroll including a spiral wrap erected on a mirror plate and meshed with the fixed scroll to perform an orbiting motion, the scroll compressor causing the orbiting scroll to perform the orbiting motion with respect to the fixed scroll to thereby form a suction chamber and a compression chamber, the scroll compressor comprising: a first space formed in a back surface center of the orbiting scroll, lubricant stored in a bottom of a sealed container being led to the first space, and the first space having pressure close to discharge pressure; a second space provided further on an outer circumference side than the first space on a back surface of the orbiting scroll, the second space having pressure between the discharge pressure and suction pressure; a first oil leak path for causing a part of oil in the first space to leak to the second space; an oil return passage for returning most of the oil in the first space to the bottom in the sealed container; a second oil leak path for causing a part of the oil in the second space to leak to the suction chamber; and a third oil leak path for allowing the oil in the second space to escape to the compression chamber to adjust the pressure in the second space according to a difference between pressure in the compression chamber and the pressure in the second space.
 2. The scroll compressor according to claim 1, wherein the third oil leak path is provided in the fixed scroll, includes a backpressure valve that opens and closes according to the difference between the pressure in the compression chamber and the pressure in the second space, and allows the oil in the second space to escape to the compression chamber to adjust the pressure in the second space.
 3. The scroll compressor according to claim 2, wherein the third oil leak path includes a backpressure valve inflow path for causing the second space and the backpressure valve to communicate and a backpressure valve outflow path for causing the compression chamber and the backpressure valve to communicate, and the backpressure valve outflow path is caused to communicate with the compression chamber after completion of a suction process and start of compression.
 4. The scroll compressor according to claim 1, wherein the third oil leak path is provided in the orbiting scroll, configured by a backpressure hole for allowing fluid in the second space to escape to the compression chamber according to the difference between the pressure in the compression chamber and the pressure in the second space, and allows the fluid in the second space to escape to the compression chamber to adjust the pressure in the second space.
 5. The scroll compressor according to claim 4, wherein the backpressure hole is configured to cause the compression chamber after completion of a suction process and start of compression and the second space to communicate.
 6. The scroll compressor according to claim 1, wherein the third oil leak path is opened in a position that communicates with both of an orbiting-outer-line-side compression chamber and an orbiting-inner-line-side compression chamber.
 7. The scroll compressor according to claim 1, wherein a orbiting boss section for coupling to a rotating shaft is provided on a back surface side of the orbiting scroll, at least a part of the first space is formed in the orbiting boss section, and the first oil leak path for causing necessary minimum oil to leak from the first space to the second space is formed on an end face side of the orbiting boss section.
 8. The scroll compressor according to claim 7, wherein the second space is formed by the fixed scroll, a frame to which the fixed scroll is attached, and the orbiting scroll, and the first space of the orbiting boss section and the second space is partitioned by a seal member provided on the orbiting boss section end face side, and the first oil leak path is configured by the seal member provided on the orbiting boss section end face side and a groove formed to intermittently supply the oil in the first space to the second space via the seal member according to an orbiting motion of the orbiting scroll.
 9. The scroll compressor according to claim 8, wherein the groove configuring the first oil leak path is configured by a slit or one or more holes formed in the orbiting boss section end face.
 10. The scroll compressor according to claim 1, wherein the second oil leak path is a groove provided on a mirror plate surface of the orbiting scroll, the groove causing the second space and the suction chamber to intermittently communicate according to the orbiting motion of the orbiting scroll.
 11. The scroll compressor according to claim 1, wherein a refrigerant having an adiabatic exponent larger than 1.09 is working fluid.
 12. A refrigeration cycle apparatus for refrigeration and air conditioning configured using the scroll compressor according to claim
 1. 